Snowmobile Rider Positioning

ABSTRACT

A snowmobile positions riders close to the center of gravity of the snowmobile, reduces jostling forces, and improves the comfort and ridability of the snowmobile. The snowmobile has a steering position on a steering device that is disposed forward of the forward-most drive axle and center of gravity of the snowmobile. A steering shaft, which operatively connects the steering device to the skis, forms an angle of less than 45 degrees with vertical. The seat may have seat positions for one, two, or three riders, the first seat position being disposed less than 590 mm behind the forward-most drive track axle. The seat may be divided into two sections, the second seat section being removably attached to the frame behind the first seat section. The back of the seat and the rearward-most seat position may be disposed behind the back end of the snowmobile&#39;s frame.

This application is a continuation of U.S. patent application Ser. No.09/877,188, filed on Jun. 11, 2001, which is a continuation-in-part ofU.S. patent application Ser. No. 09/472,134, filed on Dec. 23, 1999,both of which are incorporated herein by reference. Through U.S. patentapplication Ser. Nos. 09/877,188 and 09/472,134, this application claimsthe benefit of U.S. Provisional Patent Application No. 60/167,614, filedon Nov. 26, 1999, which is incorporated herein by reference. Thisapplication also claims the benefit of priority to Canadian PatentApplication No. 2,256,944, filed on Dec. 23, 1998, which is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the overall design andconstruction of a snowmobile, and more particularly to a design of asnowmobile that improves the driver's control over the snowmobile andthe riders' comfort.

2. Description of the Related Art

Conventional snowmobiles 110 (FIG. 1) share a common construction: theycombine features and elements so that the rider (driver) 26 sits in agenerally upright position in a location toward the rear of thesnowmobile 110. When seated in this fashion, the rider 26 sits aconsiderable distance behind the center of gravity 146 of the snowmobile110, which is located at or in proximity to the axis of the forward-mostaxle 144 of the drive track 120.

When the snowmobile 110 encounters a bump as it travels over the ground,it naturally tends to pivot about its center of gravity 146.Accordingly, the further the rider 26 is positioned from the center ofgravity 146 of the snowmobile 110, the more strongly the rider 26 willfeel each bump. This occurs because the snowmobile 110 acts as a leverthat amplifies the magnitude of the forces transferred from bumps on theground to the rider 26.

As illustrated in FIG. 1, the positions of the handlebars, seat, andfootrests of a conventional snowmobile 110 relative to its center ofgravity 146 place the driver 26 far behind the center of gravity 146 ofthe snowmobile 110. Consequently, the rider 26 experiences significantforces as the snowmobile 110 traverses each bump. When a second rider(passenger) 28 sits on the snowmobile 110 behind the driver 26 in asecond seat (2-up rider positioning), the passenger 28 is positionedeven farther away from the snowmobile's center of gravity 146 andexperiences even more uncomfortable jostling when the snowmobile 110encounters a bump.

While it would be desirable to add a third seat to accommodate a secondpassenger (third rider), it has not been done because the riders arepositioned so far back on the conventional snowmobile 110, that a thirdrider, who would be positioned even farther rearward on a third seat,would experience prohibitively large jostling forces.

Accordingly, while the positioning of the driver and passenger on theconventional snowmobile is entirely adequate for enjoying the sport ofsnowmobiling, a need has arisen for a snowmobile where the driver's andpassenger's positions are improved to minimize the effect on the ridersof the snowmobile's movement over uneven terrain.

In addition, a desire has developed for a snowmobile that maycomfortably accommodate two passengers in addition to the driver (3-uprider positioning).

SUMMARY OF THE INVENTION

The present invention improves upon the conventional design byrepositioning the riders on the snowmobile and redesigning the layout ofthe snowmobile to minimize the effect of the snowmobile's movement onthe driver and passenger(s) as they pass over uneven terrain. Thisimprovement facilitates the addition of a third seat for a third rider,who experiences a reasonably comfortable ride.

As would be understood by a person skilled in the art, a snowmobile hasa center of gravity without the rider. It should be understood that inthe context of the present invention it is assumed that the snowmobileis in running condition and is full of fuel.

In one aspect of the present invention, a snowmobile is provided with aframe, a seat disposed on the frame, first and second seat positionsdefined by the seat, an engine disposed on the frame in front of theseat, a drive track disposed below the frame and connected operativelyto the engine for propulsion of the snowmobile, a forward-most drivetrack axle disposed on the frame, two skis disposed on the frame, asteering device having a steering position, and a steering shaftoperatively connecting the two skis to the steering device for steeringthe snowmobile. The steering shaft is disposed over the engine at anangle of less than 45.degree. from vertical. The first seat position isdisposed less than 590 mm behind the forward-most drive track axle. Thesecond seat position is disposed behind the first seat position bybetween 315 mm and 365 mm.

The snowmobile may also include a third seat position disposed behindthe second seat position by between 285 mm and 370 mm.

The seat may comprise first and second seat sections. The second seatsection is removable and a cargo space may be provided below the secondseat section.

According to another aspect of the present invention, a snowmobile isprovided having a frame, a seat disposed on the frame, first and secondseat positions defined by the seat, an engine disposed on the frame infront of the seat, a drive track disposed below the frame and connectedoperatively to the engine for propulsion of the snowmobile, aforward-most drive track axle disposed on the frame, two skis disposedon the frame, a steering device having a steering position, and asteering shaft operatively connecting the two skis to the steeringdevice for steering the snowmobile. The steering position is disposedforward of the forward-most drive track axle. The first seat position isdisposed less than 590 mm behind the forward-most drive track axle. Thesecond seat position is disposed behind the first seat position bybetween 315 mm and 365 mm.

According to yet another aspect of the present invention, a snowmobileis provided having a frame, an engine disposed on the frame, a drivetrack disposed below the tunnel and connected operatively to the enginefor propulsion of the snowmobile, two skis disposed on the frame, asteering device disposed on the frame and operatively connected to thetwo skis for steering the snowmobile, and a seat disposed on the framesuch that a back end of the seat extends behind a rearward-most portionof the frame.

According to yet another aspect of the present invention, a snowmobileis provided having a frame, an engine disposed on the frame, a drivetrack disposed below the tunnel and connected operatively to the enginefor propulsion of the snowmobile, two skis disposed on the frame, asteering device disposed on the frame and operatively connected to thetwo skis for steering the snowmobile, and a seat disposed on the framesuch that a seat position defined by the seat is disposed behind arearward-most portion of the frame.

In still another aspect of the present invention, a snowmobile isprovided with a frame, a seat disposed on the frame, a seat positiondefined by the seat, an engine disposed on the frame in front of theseat, a drive track disposed below the frame and connected operativelyto the engine for propulsion of the snowmobile, a forward-most drivetrack axle disposed on the frame, two skis disposed on the frame, asteering device having a steering position, and a steering shaftoperatively connecting the two skis to the steering device for steeringthe snowmobile. The steering shaft is disposed over the engine at anangle of less than 45.degree. from vertical. The first seat position isdisposed less than 590 mm behind the forward-most drive track axle.

Other aspects of the present invention will be made more apparent in thedescription that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of the present invention will be describedwith reference to the following drawings, wherein like reference numbersdenote like features, in which:

FIG. 1 is a side view illustration of a conventional snowmobile;

FIG. 2 is a side view illustration of a snowmobile according to a firstembodiment of the present invention;

FIG. 3 is a side view illustration of a snowmobile according to a secondembodiment of the present invention;

FIGS. 4A and 4B show side views of a snowmobile according to a thirdembodiment of the present invention;

FIG. 5 is a side view illustration of a snowmobile according to a fourthembodiment of the present invention;

FIGS. 6A and 6B show side view illustrations of a snowmobile accordingto a fifth embodiment of the present invention;

FIG. 7 is a side view illustration of a snowmobile according to a sixthembodiment of the present invention;

FIG. 8 is a table comparing various dimensions of conventionalsnowmobiles and snowmobiles according to the present invention;

FIGS. 9A, 9B and 10 show the dimensions of a standard rider;

FIGS. 11A through 11D show the operation of a cover according to eitherthe third or fifth embodiment; and

FIGS. 12A through 12E show alternative seat and support arrangements foreither the third or fifth embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Throughout the description of the various embodiments of the presentinvention, reference will be made to various elements, the constructionof which is readily known to those skilled in the art. Accordingly, anexhaustive description of each and every component is not provided.Components that are similar to components in other embodiments will bereferenced by identical reference characters but with different prefixdigits.

The inventors of the present invention realized that it is possible toimprove the construction of a snowmobile to alter the positioning of theriders to considerably improve the handling and ride of the snowmobile.By shifting the steering device of the snowmobile forward, the centersof gravity of the riders are likewise shifted forward and closer to thecenter of gravity of the snowmobile. As a result, the riders experiencesignificantly less jostling when the snowmobile encounters uneventerrain. Moreover, the driver is able to maintain better control overthe snowmobile.

In addition, by moving the positioning of the first and second ridersforward, the inventors of the present invention have been able to add athird seat for a third rider behind the second rider, while avoiding theprohibitively large forces that a third rider would have experienced ona conventional snowmobile.

FIG. 8 compares various dimensions of the embodiments of the presentinvention and conventional snowmobiles 110. Reference characters A-N andrepresent variables and are commonly defined herein. With respect todistances, the positive direction is backward relative to the directionof travel of the snowmobile. Horizontal distances are measured when theunloaded (riderless) snowmobile is positioned on level ground. Some ofthe dimensions will not apply to all of the embodiments. See FIGS. 1, 2,3, 4A and 7.

Distance A is measured horizontally from the axis of the forward-mostdrive axle to the center of gravity of the unloaded snowmobile. DistanceB is measured horizontally from the steering position to the center ofgravity of the unloaded snowmobile. Distance C is measured horizontallyfrom the center of gravity of the unloaded snowmobile to the center ofgravity of a first rider (driver). Distance D is measured horizontallyfrom the center of gravity of the unloaded snowmobile to a seat positionof the first rider (driver). Distance E is measured horizontally fromthe center of gravity of the first rider to a center of gravity of asecond rider. Distance F is measured horizontally from the seat positionof the first rider (driver) to a seat position of a second rider (firstpassenger). Distance G is measured horizontally from the center ofgravity of the second rider to the center of gravity of a third rider(second passenger). Distance H is measured horizontally from the secondseat position to a third seat position. Distance I is measuredhorizontally from the center of gravity of the unloaded snowmobile to acombined center of gravity of the snowmobile and first rider. Distance Jis measured horizontally from the center of gravity of the unloadedsnowmobile to a combined center of gravity of the snowmobile, firstrider, and second rider. Distance K is measured horizontally from thecenter of gravity of the unloaded snowmobile to the combined center ofgravity of the snowmobile and first through third riders. Distance L ismeasured horizontally from the steering position to a rearward-most seatposition. Distance M is measured horizontally from the back end of theframe of the snowmobile to the back end of the second seat section.Distance N is measured horizontally from the back end of the frame ofthe snowmobile to the rear-most seat position. Angle is measured betweenvertical and an angular position of a steering shaft of the snowmobile.Lengths A-N are measured in millimeters. While FIG. 8 discloses the mostpreferred dimensions for each embodiment, the range of lengths for eachdimension according to the present invention shall be understood to bepreferably within 25 mm of the stated dimension, more preferably within15 mm of the dimension, and even more preferably within 5 mm of thedimension.

To facilitate comparison of the present invention to the conventionalsnowmobiles 110 in FIG. 8, several additional aspects of theconventional snowmobile 110 must be identified. As shown in FIG. 1, thesteering shaft 136 operatively connects the steering device 132 to theskis 116. The steering device 132 has a steering position 134, which isdefined in the same manner as in the below embodiments. The driver(first rider) 26 has a center of gravity 127, which is located slightlyforward of his torso because his arms and legs extend forward of hisbody while riding the snowmobile 110, and sits in a seat position 152.Similarly, the first passenger (second rider) 28 has a center of gravity129, and sits in a seat position 154. A combined center of gravity 170of the snowmobile 110 and the first rider 26 is located behind thecenter of gravity 146 of the snowmobile 110 without riders. A combinedcenter of gravity 172 of the snowmobile 110 and first and second riders26, 28 is located farther behind the center of gravity 146 of thesnowmobile 110 without any riders.

FIG. 2 illustrates a first embodiment of the snowmobile 10. Thesnowmobile 10 has a forward end 11 and a rearward end 13 that aredefined consistently with the travel direction of the snowmobile 10. Thesnowmobile 10 includes a body 12 (i.e., the exterior upper portions) anda frame 14. A motor 17, such as an internal combustion engine, iscarried by the frame 14 at the forward end 11. In addition, two skis 16are attached to the forward end 11 of the frame 14 through a suspensionsystem 18. It should be noted, however, that a single centered ski wouldalso work with the invention. A drive track 20 is disposed under frame14 and is connected operatively to the engine 17 for propulsion of thesnowmobile 10.

At the front 11 of the frame 14, the snowmobile 10 includes fairings 22that enclose the engine 17 to protect it and to provide an externalshell that can be decorated so that the snowmobile 10 is aestheticallypleasing. Typically, the fairings 22 comprise a hood and a bottom pad(neither of which have been individually identified in the drawingfigures). A windshield (not shown) may be connected to fairings 22 nearthe forward end 11 of snowmobile 10 in front of a steering device 32 tolessen the force of the air on the first rider (driver) 26 when thesnowmobile 10 is moving.

A straddle-type seat 50 is disposed on the frame 14 behind the engine17. The seat 50 has a first seat position 52, which is defined as aportion of the seat 50 that is adapted to support a center of a weightdistribution of the first rider 26 on the seat 50. Because snowmobilestypically have elongated straddle seats and are adapted to permit ridersto sit in a variety of front-back positions, numerous seat positionswill exist on any straddle seat. The inventors of the present inventiondefine the term “seat position” to point out particular positions on thesnowmobile that are adapted to function as the seat position for astandard rider.

FIGS. 9A, 9B and 10 illustrate the various dimensions of a standardrider of the type depicted throughout the drawings. The standard rideris a 50^(th) percentile North-American adult male. All lengths in FIGS.9A, 9B and 10 are in centimeters. The middle of each set of threedimensions represents the standard rider. The standard rider weighs 78kgs. and has the body build illustrated in FIGS. 9A, 9B and 10. Thedimensions of the standard rider are a “ruler” by which the dimensionsof the various embodiments of the snowmobile of the present inventionare measured. Riders 26, 28, 30 are standard riders.

The steering device 32, such as a handlebar, is positioned at theforward end of the snowmobile 10 above the engine 17. The steeringdevice 32 has a steering position 34, which is defined by a center of aportion of the steering device adapted to be held by the hands of therider 26. The steering position 34 is defined when the skis 16 arepositioned straight-forward. For example, if the steering device 32comprises handlebars (as illustrated in FIG. 2), the steering position34 is the center of the grips of the handlebars.

While the steering device 32 is shown in the various figures as ahandlebar, the steering device 32 should not be limited to just thisparticular construction. It would be understood by those skilled in theart that any suitable steering device 32 may be used for the snowmobile10. For example, the steering device 32 could be a steering wheel or ayoke of the type used in aircraft. In accordance with the abovedefinition of the steering position 34, if the steering device 32 is asteering wheel or yoke, the steering position 34 is the center of thesteering wheel or yoke.

Moreover, the positioning of the steering device 32 above the engine 17also should not be considered to be limited to the position illustratedin FIG. 2. As would be understood by those skilled in the art, dependingon the particular arrangement of elements for the snowmobile 10, it ispossible that the steering device 32 could be positioned higher or lowerthan shown in FIG. 2 without departing from the scope and spirit of thepresent invention.

A steering shaft 36 operatively connects the steering device 32 to thetwo skis 16 and is disposed over the engine 17 at an angle fromvertical. The inventors altered the positioning of the axis of thesteering shaft 36 so that it is more steeply sloped than steering shafts136 in prior art snowmobiles 110 having steering shafts over the engine.According to the present invention, and as illustrated in FIGS. 2 and 8,the angle is less than 45.degree. More preferably, angle lies betweenabout 25 and 40.degree. Even more preferably, angle lies between about30 and 35.degree. Most preferably, angle is about 33.degree.

There are several reasons to have a small angle. For example, the smallangle is preferred because it facilitates placement of the steeringposition 34 in a position forward of that for the conventionalsnowmobile 110. The forward position of the steering position 34 movesthe riders' 26, 28 positions closer to the center of gravity 46 of thesnowmobile 10 and improves the comfort of riders 26, 28. Additionally,the turning force applied by the rider 26 is more directly applied tosteer the snowmobile 10 when angle is small.

Because the steering device 32 is shifted forward, relative the to theconventional snowmobile 110, the steering position 34 is disposed infront of the center of gravity 46 by a distance B. According to thefirst embodiment of the present invention shown in FIG. 2, distance B isgreater than 0 and preferably between 105 mm and 155 mm. Morepreferably, distance B is between 115 mm and 145 mm. Even morepreferably, distance B is between 125 mm and 135 mm. Most preferably,distance B is about 130 mm. In contrast, the steering position 134 ofthe conventional snowmobile 110 is behind the center of gravity 146 ofthe snowmobile (see FIGS. 1 and 8) such that distance B for conventionalsnowmobiles are −160 mm for long frames and 240-mm for short frames.Long and short frames will be described later.

A drive track 20, which is operatively connected to the engine 17, ispositioned below the frame 14. The drive track 20 is a continuous beltthat runs around a number of axles including a forward-most axle 44. Thecontinuous belt has a 136 inch circumference in the first embodimentillustrated in FIG. 2 though the invention is in no way limited to asnowmobile with a particular belt size. The forward-most drive axle 44is disposed behind the steering position 34 by a distance calculated asdistance B minus distance A. According to the present invention, theforward-most drive axle 44 is disposed behind the steering position 34.Preferably, the distance is between 40 mm and 90 mm. More preferably,the distance is between 50 mm and 80 mm. Even more preferably, thedistance is between 60 mm and 70 mm. Most preferably, the distance isabout 65 mm. In contrast, the steering positions 134 on conventionalsnowmobiles are positioned behind the forward-most drive 144 axle by 270mm (see FIGS. 1 and 8).

Two footrests are positioned on either side of seat 50 to accommodatethe feet of the riders 26, 28. The footrests extend outwardly from theframe 14. The footrests may be disposed in a horizontal orientation, oralternatively, in an angled orientation.

An adjustable backrest 92 is attached to the seat 50 near the back endof the seat 50. Various embodiments of the backrest 92 are describedthroughout the specification, where preferred. As would be understood bythose skilled in the art, the backrest 92 need not have only theconstruction shown or be located in the position depicted. In fact, thebackrest 92 need not be provided at all.

The first seat position 52 is located behind the forward-most drive axle44 by a horizontal distance calculated as distance D plus distance A.According to the present invention, this distance is less than 590 mmand preferably between 540 mm and 590 mm. More preferably, this distanceis between 550 mm and 580 mm. Even more preferably, this distance isbetween 560 mm and 570 mm. Most preferably, this distance is about 565mm. In contrast, the first seat position 152 in conventional snowmobiles110 is a much larger 905 mm behind the forward-most drive axle 144 (seeFIGS. 1 and 8).

A second seat position 54 is disposed on the seat 50 behind the firstseat position 52 and is adapted to accommodate a second rider 28 (firstpassenger) behind the driver 26 (first rider). As the rider 26 ispositioned closer to the center of gravity 46 of the snowmobile 10 thanon a conventional snowmobile 110, the ride for the second rider 28 onthe snowmobile 10 is improved because the second rider 28 is alsodisposed closer to the center of gravity 46 of the snowmobile 10 (bycomparison with a second rider 28 on a conventional snowmobile 110). Thesecond seat position 54 is disposed a distance F behind the first seatposition 52. According to this embodiment, distance F is between 315 mmand 365 mm. Preferably, distance F is between 325 mm and 355 mm. Morepreferably, distance F is between 335 mm and 345 mm. Most preferably,distance F is about 340 mm. Consequently, the second seat position 54 ofthe second rider 28 is most preferably about 840 mm behind the center ofgravity 46 of snowmobile 10 (distance D plus distance F). As illustratedin FIG. 8 the first seat position 152 on a conventional short framesnowmobile 110 is 875 mm behind the center of gravity 146 and 795 mmbehind the center of gravity 146 of a conventional long frame snowmobile110 (distance D). As the position of the second rider 28 relative to thesnowmobile's center of gravity 46 is similar to a position of a firstrider (driver) 26 of a conventional snowmobile 110 relative to theconventional snowmobile's center of gravity 146, the second rider 28 onthe snowmobile 10 of the present invention experiences forces similar tothe forces experienced by the driver 26 of a conventional snowmobile110.

In this embodiment, the first and second seat positions 52, 54 aredisposed on the seat 50, which comprises an integral seat unit. Theintegral seat unit 50 may be rigidly mounted to the snowmobile 10 or itmay be removably mounted.

A center of gravity 70 of the combined weight of the snowmobile 10 andrider 26 is disposed behind the center of gravity 46 of the snowmobile10 without a rider. A center of gravity 72 of the combined weight of thesnowmobile 10 and two riders 26, 28 is disposed farther rearward of thecenter of gravity 46. The first rider 26 has a center of gravity 27,which is positioned slightly forward of the rider's 26 torso because therider's arms and legs are in a forwardly-extending position. Similarly,the second rider 28 has a center of gravity 29.

As illustrated in FIG. 8, the centers of gravity of the riders 26, 28 ofthe snowmobile 10 are positioned closer to the center of gravity 46 ofsnowmobile 10 than in conventional snowmobiles 110. The center ofgravity 27 of the first rider 26 on the snowmobile 10 is preferablybetween 325 mm and 375 mm behind the center of gravity 46 of thesnowmobile 10, more preferably between 335 mm and 365 mm behind thecenter of gravity 46, even more preferably between 345 mm and 355 mmbehind the center of gravity 46, and most preferably about 350 mm(distance C) behind the center of gravity 46. In contrast, the center ofgravity 127 of the first rider 26 on a conventional snowmobile 110 isdisposed behind the center of gravity 146 of the convention snowmobile110 by 645 mm for long frames and 725 mm for short frames.

The center of gravity 29 of a second rider 28 on the snowmobile 10 isdisposed behind the center of gravity 46 of the snowmobile 10 by adistance calculated as distance C plus distance E. This distance ispreferably between 695 mm and 745 mm, more preferably between 705 mm and735 mm, even more preferably between 715 mm and 725 mm, and mostpreferably about 720 mm. In contrast, the center of gravity 129 of asecond rider 128 on a conventional snowmobile 110 is disposed behind thecenter of gravity 146 of the conventional snowmobile 110 by 1015 mm forshort frames and by 1095 mm for long frames.

FIG. 3 illustrates a second embodiment of the present invention. Thesnowmobile 210 of the second embodiment has a shorter frame 214 than theframe 14 of the snowmobile 10 of the first embodiment. The frame 14preferably has a length of about 1913 mm. The frame 214 preferably has alength of about 1493 mm. The difference in length between the long frameand the short frame is approximately 420 mm. The long frame provides fortwo permanent seats and a larger cargo space. In addition, the longframe is simpler and less expensive to manufacture than the short frameas it has less moving parts, and less parts in general, than the shortframe. The shorter frame 214, however, provides the driver 26 with thefeeling that the snowmobile is lighter and more maneuverable than asnowmobile having the long frame. The short frame also reduces the polarmoment of inertial of the snowmobile about the vertical axis. The shortframe also provides a tail landing for the snowmobile (i.e., the shortframe provides more space for a rear idler wheel to travel higher uponcompression of the rear suspension). It should be appreciated that theframe 14 and the frame 214 may have lengths that differ from thepreferred embodiments discussed above.

In the second embodiment shown in FIG. 3, a 121 inch drive track 220 isillustrated instead of the 136 inch track 20 of the snowmobile 10 of thefirst embodiment. The short frame 214 and the 121 inch drive track 220reduce the rotational inertia of snowmobile 210 and consequently improveits handling performance. As a result of these differences, some of thedimensions are correspondingly altered as shown in FIG. 8.

A steering shaft 36 operatively connects the skis 16 to the steeringdevice 32. The axis of the steering shaft 36 forms an angle withvertical that is the same as the orientation described in relation tothe first embodiment illustrated in FIG. 2. As in the first embodiment,the angular position of the steering shaft 36 permits placement of thesteering position 34 in a position forward of that for the conventionalsnowmobile 110, which moves the positions of the riders 26, 28 closer tothe center of gravity 246 of the snowmobile 210 and improves the comfortof the riders 26, 28.

Because the steering device 32 is shifted forward relative toconventional snowmobiles 110, the forward-most drive axle 244 isdisposed behind the steering position 34 by a distance calculated asdistance B minus distance A. According to the present embodiment, thisdistance is positive. Preferably, the distance is between 40 mm and 90mm. More preferably, the distance is between 50 mm and 80 mm. Even morepreferably, the distance is between 60 mm and 70 mm. Most preferably,the distance is about 65 mm. In contrast, the steering positions 134 onconventional snowmobiles 110 are positioned behind the forward-mostdrive axle 144 by 270 mm (see FIGS. 1 and 8).

A first seat position 252 is defined on the seat 250 behind theforward-most drive axle 244 by a horizontal distance calculated asdistance D plus distance A. While this distance is always positive, itis preferably between 540 mm and 590 mm. More preferably, this distanceis between 550 mm and 580 mm. Even more preferably, this distance isbetween 560 mm and 570 mm. Most preferably, this distance is about 565mm. In contrast, the first seat position 152 in conventional snowmobiles110 is a much larger 905 mm behind the forward-most drive axle 144 (seeFIGS. 1 and 8).

A second seat position 254 is disposed a horizontal distance F behindthe first seat position 252. According to this embodiment, distance F isbetween 315 mm and 365 mm. Preferably, distance F is between 325 mm and355 mm. More preferably, distance F is between 335 mm and 345 mm. Mostpreferably, distance F is about 340 mm.

Like the seat 50 of the first embodiment, the seat 250 may comprise anintegral seat unit that may either be rigidly mounted to the snowmobile210 or may be removable. Alternatively, the seat 250 may include morethan one section.

A center of gravity 270 of the combined weight of the snowmobile 210 andrider 26 is disposed behind the center of gravity 246 of the snowmobile210 without a rider. A center of gravity 272 of the combined weight ofthe snowmobile 210 and two riders 26, 28 is disposed farther rearward ofthe center of gravity 246. The first rider 26 has a center of gravity227, which is positioned slightly forward of the rider's 26 torsobecause the rider's arms and legs are in a forwardly-extending position.Similarly, the second rider 28 has a center of gravity 229.

The centers of gravity 227, 229 of the riders 26, 28, respectively, ofthe snowmobile 210 are positioned closer to the center of gravity 246 ofsnowmobile 210 than in conventional snowmobiles 110 (see distances C andE in FIG. 8). The center of gravity 227 of the first rider 26 on thesnowmobile 210 is preferably between 295 mm and 345 mm behind the centerof gravity 246 of the snowmobile 210, more preferably between 305 mm and335 mm behind the center of gravity 246, even more preferably between315 mm and 325 mm behind the center of gravity 246, and most preferablyabout 320 mm behind the center of gravity 246.

The center of gravity 229 of a second rider 28 on the snowmobile 210 isdisposed behind the center of gravity 246 of the snowmobile 210 by adistance calculated as distance C plus distance E. This distance ispreferably between 665 mm and 715 mm, more preferably between 675 mm and705 mm, even more preferably between 685 mm and 695 mm, and mostpreferably about 690 mm.

FIGS. 4A and 4B illustrate a third embodiment of the present invention.Like the snowmobile 210 of the second embodiment, the snowmobile 310 hasa short frame 314 and a 121 inch drive track 320.

As with the previous embodiments, the axis of the steering shaft 36forms an angle with vertical that is less than 45 degrees. As in thefirst embodiment, the angular position of steering shaft 36 permitsplacement of steering position 34 in a position forward of that for theconventional snowmobile 110, which moves the positions of the riders 26,28 closer to the center of gravity 346 of the snowmobile 310 andimproves the comfort of the riders 26, 28.

The forward-most drive axle 344 is disposed behind the steering position34 by a distance calculated as distance B minus distance A. According tothe present invention, the distance is positive. Preferably, thedistance is between 40 mm and 90 mm. More preferably, the distance isbetween 50 mm and 80 mm. Even more preferably, the distance is between60 mm and 70 mm. Most preferably, the distance is about 65 mm. Incontrast, the forward-most drive axle on conventional snowmobiles ispositioned in front of the steering position by 270 mm (see FIG. 8).

The seat 350 comprises a first seat section 350′ and a second seatsection 350″. In this embodiment, the second seat section 350″ isremovable. A cargo space 394, which is preferably plastic, is providedbehind the first seat section 350′ beneath the second removable seatsection 350″. As shown in FIGS. 11A through 11D, a cover 395 can beattached over the cargo space 394 to enclose the cargo space 394 whenthe second seat section 350″ is not attached. The cover 395 is hinged tothe cargo space 394. One or more latches are provided to secure thecover 395 in a closed position.

A first seat position 352 is defined on the first seat section 350′behind the forward-most drive axle 344 by a horizontal distancecalculated as distance D plus distance A. According to the presentinvention, this distance is less than 590 mm and preferably between 540mm and 590 mm. More preferably, this distance is between 550 mm and 580mm. Even more preferably, this distance is between 560 mm and 570 mm.Most preferably, this distance is about 565 mm. In contrast, the firstseat position 152 in conventional snowmobiles 110 is a much larger 905mm behind the forward-most drive axle 144 (see FIGS. 1 and 8).

A second seat position 354 is defined on the second seat section 350″ ahorizontal distance F behind the first seat position 352. According tothis embodiment, distance F is between 315 mm and 365 mm. Preferably,distance F is between 325 mm and 355 mm. More preferably, distance F isbetween 335 mm and 345 mm. Most preferably, distance F is about 340 mm.

A support element 360 extends upwardly and rearwardly from the frame314. Fasteners (not shown) are used to secure the second seat 350 to theframe 314 via the support element 360. FIG. 4B shows an enlarged sideview of the removable second seat section 350″.

A tunnel 314′ forms the back end 314″ of the frame 314. The drive track320 is mounted below the tunnel 314′. A snow flap 380 extends rearwardlybehind the back end 314″.

As shown in FIG. 4A, the support element 360 extends rearwardly beyondthe back end 314″ of the frame 314 to structurally support the secondseat section 350″ behind the back end 314″. The second seat position 354is disposed on the second seat section 350 a distance N behind the backend 314″ of the frame 314. For this embodiment, distance N is alwaysgreater than zero. Preferably, distance N is between 55 mm and 105 mm.More preferably, distance N is between 65 mm and 95 mm. Even morepreferably, distance N is between 75 mm and 85 mm. Most preferably,distance N is about 80 mm. In contrast, the second seat positions 154 ofconventional snowmobiles 110 do not extend behind the back end of theframe because the second rider 28 would be prohibitively far away fromthe center of gravity 146 of the snowmobile 110. Conventionalsnowmobiles 110 position the second seat position 154 in front of theback end of the frame by 290 mm for long frames and 120 mm for shortframes (see FIGS. 1 and 8).

A rearward-most end of seat section 350″ is disposed a distance M behindthe back end 314″ of the frame 314. For this embodiment, distance M isalways greater than zero. Preferably, distance M is between 205 mm and255 mm. More preferably, distance M is between 215 mm and 245 mm. Evenmore preferably, distance N is between 225 mm and 235 mm. Mostpreferably, distance M is about 230 mm. In contrast, the rearward-mostend of the seat of conventional snowmobiles 110 is disposed in front ofthe back end of the frame by 50 mm for long frames and at the back endof the frame for short frames (i.e., 0 mm, see FIG. 8).

A center of gravity 370 of the combined weight of the snowmobile 310 andrider 26 is disposed behind the center of gravity 346 of the snowmobile310 without a rider. A center of gravity 372 of the combined weight ofthe snowmobile 310 and two riders 26, 28 is disposed farther rearward ofthe center of gravity 346. The first rider 26 has a center of gravity327, which is positioned slightly forward of the rider's 26 torsobecause the rider's arms and legs are in a forwardly-extending position.Similarly, the second rider 28 has a center of gravity 329.

As illustrated in FIG. 8, the centers of gravity 327, 329 of the riders26, 28 of the snowmobile 310 are positioned closer to the center ofgravity 346 of snowmobile 310 than the centers of gravity 127, 129 arepositioned to the center of gravity 146 in conventional snowmobiles 110.The center of gravity 327 of the first rider 26 on the snowmobile 310 ispreferably between 295 mm and 345 mm behind the center of gravity 346 ofthe snowmobile 310, more preferably between 305 and 335 mm behind thecenter of gravity 346, even more preferably between 315 and 325 mmbehind the center of gravity 346, and most preferably about 320 mmbehind the center of gravity 346.

The center of gravity 329 of a second rider 28 on the snowmobile 310 isdisposed behind the center of gravity 346 of the snowmobile 310 by adistance calculated as distance C plus distance E. This distance ispreferably between 665 mm and 715 mm, more preferably between 675 mm and705 mm, even more preferably between 685 mm and 695 mm, and mostpreferably about 690 mm.

FIG. 5 illustrates a fourth embodiment of the present invention. Likethe snowmobile 10 of the first embodiment, the snowmobile 410 has a longframe 414 and a 136 inch drive track 20.

As with the first embodiment, the axis of the steering shaft 36 forms anangle with vertical that is less than 45 degrees. Similarly, the angularposition of steering shaft 36 permits placement of steering position 34in a position forward of that for the conventional snowmobile 110, whichmoves the positions of the riders 26, 28 closer to the center of gravity446 of the snowmobile 410 and improves the comfort of the riders 26, 28.

The forward-most drive axle 444 is disposed behind the steering position34 by a distance calculated as distance B minus distance A. According tothe present invention, the forward-most drive axle 444 is disposedbehind the steering position 34. Preferably, the distance is between 40mm and 90 mm. More preferably, the distance is between 50 mm and 80 mm.Even more preferably, the distance is between 60 mm and 70 mm. Mostpreferably, the distance is about 65 mm. In contrast, the steeringpositions 134 on conventional snowmobiles 110 are positioned behind theforward-most drive axle 144 by 270 mm (see FIGS. 1 and 8).

Like the seat 50 of the first embodiment, the seat 450 of snowmobile 410comprises an integral seat unit that may either be rigidly mounted tothe snowmobile 410 or removable. A first seat position 452 is defined onthe seat 450 behind the forward-most drive axle 444 by a horizontaldistance calculated as distance D plus distance A. According to thepresent invention, this distance is less than 590 mm and preferablybetween 540 mm and 590 mm. More preferably, this distance is between 550mm and 580 mm. Even more preferably, this distance is between 560 mm and570 mm. Most preferably, this distance is about 565 mm. In contrast, thefirst seat position 152 in conventional snowmobiles 110 is a much larger905 mm behind the forward-most drive axle (see FIG. 8).

A second seat position 454 is disposed on the seat 450 a horizontaldistance F behind the first seat position 452. According to thisembodiment, distance F is between 315 mm and 365 mm. Preferably,distance F is between 325 mm and 355 mm. More preferably, distance F isbetween 335 mm and 345 mm. Most preferably, distance F is about 340 mm.Consequently, the seat position 454 of the second rider 28 is mostpreferably about 735 mm behind the center of gravity 446 of snowmobile410 (distance D plus distance F).

A third seat position 456 is added behind the second seat position 454on the seat 450 in order to accommodate a third rider 30. The forwardplacement of the steering position 34 permits a third rider 30 to ridethe snowmobile 410 without experiencing prohibitively large jostlingforces. The center of gravity 431 of the third rider 30 is positionedbehind the center of gravity of snowmobile 410 by a distance calculatedas distance C plus distance E plus distance G, which is preferablybetween 900 mm and 950 mm. The distance is more preferably between 910mm and 940 mm. The distance is even more preferably between 920 mm and930 mm. The distance is most preferably about 925 mm. In contrast, thesecond rider 28 on the conventional snowmobile 110 is positioned behindthe center of gravity 146 of the conventional snowmobile 110 by 1015 mmfor a long frame and 1095 mm for a short frame (distance C plus distanceE). Consequently, the third rider 30 (second passenger) on snowmobile410 is closer to the center of gravity 446 of the snowmobile 410 andexperiences less jostling forces than a second rider 28 (firstpassenger) would normally experience on a conventional snowmobile 110.

A center of gravity 470 of the combined weight of the snowmobile 410 andrider 26 is disposed behind the center of gravity 446 of the snowmobile410 without a rider. A center of gravity 472 of the combined weight ofthe snowmobile 410 and two riders 26, 28 is disposed farther rearward ofthe center of gravity 446 of the riderless snowmobile 410. A center ofgravity 474 of the combined weight of the snowmobile 410 and threeriders 26, 28, 30 is disposed even farther rearward of the center ofgravity 446 of the riderless snowmobile 410. The first rider 26 has acenter of gravity 427, which is positioned slightly forward of therider's 26 torso because the rider's arms and legs are in aforwardly-extending position. Similarly, the second and third riders 28,30 have centers of gravity 429, 431, respectively.

FIG. 8 illustrates the relevant spatial relationships for the fourthembodiment and shows that the centers of gravity of the riders 26, 28,30 are disposed closer to the center of gravity 446 of the snowmobilethan in conventional snowmobiles 110.

The center of gravity 427 of the first rider 26 on the snowmobile 410 ispreferably between 220 mm and 270 mm behind the center of gravity 446 ofthe snowmobile 410, more preferably between 230 mm and 260 mm behind thecenter of gravity 446, even more preferably between 240 mm and 250 mmbehind the center of gravity 446, and most preferably about 245 mmbehind the center of gravity 446.

The center of gravity 429 of a second rider 28 on the snowmobile 410 isdisposed behind the center of gravity 446 of the snowmobile 410 by adistance calculated as distance C plus distance E. This distance ispreferably between 590 mm and 640 mm, more preferably between 600 mm and630 mm, even more preferably between 610 mm and 620 mm, and mostpreferably about 615 mm.

The center of gravity 431 of the third rider 30 on the snowmobile 410 isdisposed behind the center of gravity 446 of the snowmobile 410 by adistance calculated as distance C plus distance E plus distance G. Thisdistance is preferably between 900 mm and 950 mm, more preferablybetween 910 mm and 940 mm, even more preferably between 920 mm and 930mm, and most preferably about 925 mm.

A horizontal distance H between the second seat position 454 the thirdseat position 456 is preferably between 285 mm and 335 mm. Distance H ismore preferably between 295 mm and 325 mm. Distance H is even morepreferably between 305 mm and 315 mm. Distance H is most preferablyabout 310 mm. A horizontal distance G between the center of gravity 429of the second rider 428 and the center of gravity 431 of the third rider430 is about the same as distance H for this embodiment (see FIG. 8).

FIGS. 6A and 6B illustrate a fifth embodiment of the present invention.Like the snowmobile 10 of the first embodiment, snowmobile 510 has along frame 514 and a 136 inch drive track 520. As in previousembodiments, the axis of the steering shaft 36 forms an angle withvertical that is less than 45 degrees. The forward-most drive axle 544is disposed behind the steering position 34 by a distance calculated asdistance B minus distance A. According to this embodiment, theforward-most drive axle 544 is disposed behind the steering position 34.Preferably, the distance is between 40 mm and 90 mm. More preferably,the distance is between 50 mm and 80 mm. Even more preferably, thedistance is between 60 mm and 70 mm. Most preferably, the distance isabout 65 mm.

Similar to the seat 350 of the snowmobile 310 of the third embodiment,seat 550 is formed by a first seat section 550′ and a second seatsection 550″. The second seat section 550″ is removable. When the secondseat section 550″ is removed, a cover 395 (as illustrated in FIGS. 11A-Dand discussed with respect to the third embodiment) may be used to covera cargo space 594 that is located beneath the second seat section 550″and behind the first seat section 550′.

A first seat position 552 is defined on the first seat section 550′behind the forward-most drive axle 544 by a horizontal distancecalculated as distance D plus distance A. According to the presentinvention, this distance is less than 590 mm and preferably between 540mm and 590 mm. More preferably, this distance is between 550 mm and 580mm. Even more preferably, this distance is between 560 mm and 570 mm.Most preferably, this distance is about 565 mm.

A second seat position 554 is disposed on the first seat section 550′ ahorizontal distance F behind the first seat position 552. According tothis embodiment, distance F is between 265 mm and 315 mm. Preferably,distance F is between 275 mm and 305 mm. More preferably, distance F isbetween 285 mm and 295 mm. Most preferably, distance F is about 290 mm.

A third seat position 556 is positioned on the second seat section 550″behind the second seat position 554 by a horizontal distance H, which ispreferably between 320 mm and 370 mm. Distance H is more preferablybetween 330 mm and 360 mm. Distance H is even more preferably between340 mm and 350 mm. Distance H is most preferably about 345 mm.

A tunnel 514′ forms the back end 514″ of the frame 514. The drive track520 is mounted below the tunnel 514′. A snow flap 580 extends rearwardlybehind the back end 514″.

As in the third embodiment, a support element 560 extends upwardly andrearwardly from the back end 514″ of the frame 514 to provide supportfor the second seat section 550″. The third seat position 556 and backend of the third seat position 556 extend behind the back end 514″ ofthe frame 514 by distances N and M, respectively. Distance N is alwayspositive and preferably between 35 mm and 85 mm. Distance N is morepreferably between 45 mm and 75 mm. Distance N is even more preferablybetween 55 mm and 65 mm. Distance N is most preferably about 60 mm.Distance M is always positive and preferably between 265 mm and 315 mm.Distance M is more preferably between 275 mm and 305 mm. Distance M iseven more preferably between 285 mm and 295 mm. Distance M is mostpreferably about 290 mm.

A center of gravity 570 of the combined weight of the snowmobile 410 andrider 26 is disposed behind the center of gravity 546 of the snowmobile510 without a rider. A center of gravity 572 of the combined weight ofthe snowmobile 510 and two riders 26, 28 is disposed farther rearward ofthe center of gravity 546 of the riderless snowmobile 510. A center ofgravity 574 of the combined weight of the snowmobile 510 and threeriders 26, 28, 30 is disposed even farther rearward of the center ofgravity 546 of the riderless snowmobile 410. The first rider 26 has acenter of gravity 527, which is positioned slightly forward of therider's 26 torso because the rider's arms and legs are in aforwardly-extending position. Similarly, the second and third riders 28,30 have centers of gravity 529, 531, respectively.

FIG. 8 illustrates the relevant spatial relationships for the fifthembodiment and illustrates that the centers of gravity of the riders 26,28, 30 are disposed closer to the center of gravity 546 of thesnowmobile 510 than in the conventional snowmobiles 110.

The center of gravity 527 of the first rider 26 on the snowmobile 510 ispreferably between 220 mm and 270 mm behind the center of gravity 546 ofthe snowmobile 510, more preferably between 230 mm and 260 mm behind thecenter of gravity 546, even more preferably between 240 mm and 250 mmbehind the center of gravity 546, and most preferably about 245 mmbehind the center of gravity 546.

The center of gravity 529 of a second rider 28 on the snowmobile 510 isdisposed behind the center of gravity 546 of the snowmobile 510 by adistance calculated as distance C plus distance E. This distance ispreferably between 590 mm and 640 mm, more preferably between 600 mm and630 mm, even more preferably between 610 mm and 620 mm, and mostpreferably about 615 mm.

The center of gravity 531 of the third rider 30 on the snowmobile 510 isdisposed behind the center of gravity 546 of the snowmobile 510 by adistance calculated as distance C plus distance E plus distance G. Thisdistance is preferably between 935 mm and 985 mm, more preferablybetween 945 mm and 975 mm, even more preferably between 955 mm and 965mm, and most preferably about 960 mm.

It should be noted that while the third and fifth embodiments include aremovable back seat that simply attaches to the support element 360,560, other ways of creating a removable seat section, which are known bythose of ordinary skill in the art, are also intended to be included inthe invention. For example, a second seat section might be slidablealong a longitudinal track such that a third seat could be inserted likea leaf of a table between the first and second seats. Similarly, abackrest might be slidably mounted to a longitudinal track behind afirst seat and permit the insertion of second and/or third seats betweenthe first seat and the backrest.

Furthermore, while the third and fifth embodiments illustrate particularembodiments of the second seat sections 350, 550 and support pieces 360,560, numerous other embodiments of such components, which would beapparent to those skilled in the art, could also be utilized and areintended to be included in the present invention. For example, FIGS. 12Athrough 12E illustrate several alternative seats having first seatsections 650′, 750′, 850′, 950′, 1050′, second seat sections 650″, 750″,850″, 950″, 1050″, and support pieces 660, 760, 860, 960, 1060.

FIG. 7 illustrates a sixth embodiment of the snowmobile 610. Thesnowmobile 610 of the sixth embodiment may have a short or long frame614 and a snow flap 680 extending from the back end of the frame 614.The snowmobile 610 has a 136 inch drive track 620.

As with the previous embodiments, the axis of the steering shaft 36forms an angle with vertical that is less than 45 degrees. As in thefirst embodiment, the angular position of steering shaft 36 permitsplacement of steering position 34 in a position forward of that for theconventional snowmobile 110, which moves the position of the driver 26closer to the center of gravity 646 of the snowmobile 610 and improvesthe comfort of the driver 26.

The forward-most drive axle 644 is disposed behind the steering position34 by a distance calculated as distance B minus distance A. According tothe present invention, the distance is positive. Preferably, thedistance is between 40 mm and 90 mm. More preferably, the distance isbetween 50 mm and 80 mm. Even more preferably, the distance is between60 mm and 70 mm. Most preferably, the distance is about 65 mm. Incontrast, the forward-most drive axle 144 on conventional snowmobiles110 is positioned in front of the steering position 134 by 270 mm (seeFIG. 8).

The snowmobile 610 has a seat 650 configured for a single rider 26 (1-uprider positioning) that defines a seat position 652. The seat position652 is behind the forward-most drive axle 644 by a horizontal distancecalculated as distance D plus distance A. According to the presentinvention, this distance is less than 590 mm and preferably between 540mm and 590 mm. More preferably, this distance is between 550 mm and 580mm. Even more preferably, this distance is between 560 mm and 570 mm.Most preferably, this distance is about 565 mm. In contrast, the firstseat position 152 in conventional snowmobiles 110 is a much larger 905mm behind the forward-most drive axle 144 (see FIGS. 1 and 8).

As illustrated in FIG. 7, the center of gravity 627 of the rider 26 ofthe snowmobile 610 is positioned closer to the center of gravity 646 ofthe snowmobile 610 than in conventional snowmobiles 110. The center ofgravity 627 of the rider 26 on the snowmobile 610 is preferably between295 mm and 345 mm behind the center of gravity 646 of the snowmobile610, more preferably between 305 mm and 335 mm behind the center ofgravity 646, even more preferably between 315 mm and 325 mm behind thecenter of gravity 646, and most preferably about 320 mm behind thecenter of gravity 646.

While the invention has been described with reference to the variousexemplary embodiments outlined above, it will be understood by thoseskilled in the art that various changes may be made and equivalents maybe substituted for elements thereof without departing from the spiritand scope of the present invention. In addition, many modifications maybe made to adapt a particular situation, component, or material to theteachings of the present invention without departing from its teachingsas claimed.

1. A snowmobile, comprising: a frame; a straddle-type seat disposed onthe frame; first and second seat positions defined by the seat; anengine disposed on the frame in front of the seat; a drive trackdisposed below the frame and connected operatively to the engine forpropulsion of the snowmobile; a forward-most drive track axle disposedon the frame; two skis disposed on the frame; a steering device having asteering position; and a steering shaft operatively connecting the twoskis to the steering device for steering the snowmobile, the first seatposition is disposed less than 590 mm behind the forward-most drivetrack axle, the second seat position is disposed behind the first seatposition by between 265 mm and 365 mm.
 2. The snowmobile of claim 1,wherein the steering shaft is disposed over the engine at an angle ε ofbetween 25° and 40° from vertical.
 3. The snowmobile of claim 1, whereinthe first seat position is disposed between 550 mm and 580 mm behind theforward-most drive track axle.
 4. The snowmobile of claim 1, wherein thesecond seat position is disposed behind the first seat position bybetween 325 mm and 355 mm.
 5. The snowmobile of claim 1, wherein thesecond seat position is disposed behind the first seat position bybetween 275 mm and 305 mm.
 6. The snowmobile of claim 1 furthercomprising a third seat position on the seat, wherein the third seatposition is disposed behind the second seat position by between 285 mmand 370 mm.
 7. The snowmobile of claim 6, wherein the third seatposition is disposed behind the second seat position by between 330 mmand 360 mm.
 8. The snowmobile of claim 1, wherein the first and secondseat positions are disposed on a singular seat unit.
 9. The snowmobileof claim 1, wherein the seat comprises first and second seat sections,the second seat section being removable, the first seat position beingon the first seat section, and the second seat position being on thesecond seat section.
 10. The snowmobile of claim 9, wherein a cargospace is provided behind the first seat section beneath the secondremovable seat section.
 11. The snowmobile of claim 6, wherein thefirst, second, and third seat positions are disposed on a singular seatunit.
 12. The snowmobile of claim 6, wherein the seat comprises firstand second seat sections, the second seat section being removable, thefirst and second seat positions being on the first seat section, and thethird seat position being on the second seat section.
 13. A snowmobile,comprising: a frame including a tunnel; an engine disposed on the frame;a drive track disposed below the tunnel and connected operatively to theengine for propulsion of the snowmobile; a forward-most drive track axledisposed on the frame; two skis disposed on the frame; a steering devicedisposed on the frame and operatively connected to the two skis forsteering the snowmobile, the steering device having a steering position;a steering shaft operatively connecting the two skis to the steeringdevice for steering the snowmobile; and a straddle-type seat disposed onthe frame, wherein a back end of the seat extends behind a rearward-mostportion of the frame; and a front suspension system operativelyconnecting the two skis to the frame, wherein the front suspensionsystem is one of an A-arm suspension system and a trailing armsuspension system.
 14. The snowmobile of claim 13, wherein the back endof the seat extends behind the rearward-most portion of the frame bybetween 205 mm and 255 mm.
 15. The snowmobile of claim 13, wherein theseat comprises first, second and third seating positions, the seatfurther comprising first and second seat sections, the second seatsection being removable, the first and second seat positions being onthe first seat section, and the third seat position being on the secondseat section.
 16. A snowmobile, comprising: a frame; a straddle-typeseat disposed on the frame; a seat position defined by the seat; anengine disposed on the frame in front of the seat; a drive trackdisposed below the frame and connected operatively to the engine forpropulsion of the snowmobile; a forward-most drive track axle disposedon the frame; two skis disposed on the frame; a steering device having asteering position; and a steering shaft operatively connecting the twoskis to the steering device for steering the snowmobile, wherein theseat position is disposed less than 590 mm behind the forward-most drivetrack axle.
 17. The snowmobile of claim 16, wherein the seat position isdisposed between 550 mm and 580 mm behind the forward-most drive trackaxle.
 18. The snowmobile of claim 17, wherein the seat position isdisposed between 560 mm and 570 mm behind the forward-most drive trackaxle.
 19. The snowmobile of claim 16, further comprising a frontsuspension system operatively connecting the two skis to the frame,wherein the front suspension system is one of an A-arm suspension systemand a trailing arm suspension system.
 20. The snowmobile of claim 16,wherein the seat position is a first seat position, the seat furthercomprises second and third seating positions, the seat furthercomprising first and second seat sections, the second seat section beingremovable, the first and second seat positions being on the first seatsection, and the third seat position being on the second seat section.